Breathing muscles of patients with conditions such as obstructive lung diseases must work unusually hard to overcome an increased resistance to airflow often associated with such conditions. This increased work of breathing (WOB) often causes the patient to feel short of breath, and can be so severe in some circumstances that the breathing muscles are unable to maintain normal oxygen levels in the blood.
When increased WOB requires treatment, therapy may be indicated to increase the blood oxygen level. This is conventionally accomplished in one of two primary ways. The first line of treatment is to increase the oxygen percentage in the inspired air, using supplementary oxygen. If this therapy fails, the next level of treatment is to decrease WOB using positive pressure to assist inspiration. Positive airway pressure (PAP) may be continuous (CPAP) or bi-phasic so that higher pressure is supplied during inspiration than during expiration. PAP is usually applied by blowing oxygen-enriched air into a sealed face mask from a device that regulates the mask pressure by varying the gas flow rate.
Nevertheless, there remains a need for an improved method for reducing the work of breathing.